package com.lxz.rpc.demo;

import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.lang.reflect.InvocationHandler;
import java.lang.reflect.Method;
import java.lang.reflect.Proxy;
import java.net.ServerSocket;
import java.net.Socket;

public class RpcFramework {
	/**
	 * 暴露服务
	 * 
	 * @param service 服务实现
	 * @param port 服务端口
	 * @throws Exception 
	 */
	public static void export(final Object service, int port) throws Exception{
		if(service == null){
			throw new IllegalArgumentException("service instance == null");
		}
		if(port <= 0 || port > 65535){
			throw new IllegalArgumentException("Invalid port " + port);
		}
		System.out.println("Export service " + service.getClass().getName() + " on port " + port);
		ServerSocket server = new ServerSocket(port);
		for(;;){
			try{
				final Socket socket = server.accept();
				new Thread(new Runnable(){
					public void run() {
						try{
							try{
								ObjectInputStream input = new ObjectInputStream(socket.getInputStream());
								try{
									String methosName = input.readUTF();
									Class<?>[] parameterTypes = (Class<?>[]) input.readObject();
									Object[] arguments = (Object[]) input.readObject();
									ObjectOutputStream output = new ObjectOutputStream(socket.getOutputStream());
									try{
										Method method = service.getClass().getMethod(methosName, parameterTypes);
										Object result = method.invoke(service, arguments);
										output.writeObject(result);
									} catch(Throwable t){
										output.writeObject(t);
									} finally{
										output.close();
									}
								} finally{
									input.close();
								}
							} finally{
								socket.close();
							}
						} catch(Exception e){
							e.printStackTrace();
						}
					}
				}).start();
			} catch(Exception e){
				e.printStackTrace();
			}
		}
	}
	
	/**
	 * 引用服务
	 * 
	 * @param <T> 接口泛型
	 * @param interfaceClass 接口类型
	 * @param host 服务器主机名
	 * @param port 服务器端口
	 * @return 远程服务
	 * @throws Exception
	 */
	@SuppressWarnings("unchecked")
	public static <T> T refer(final Class<T> interfaceClass, final String host, final int port){
		if(interfaceClass == null){
			throw new IllegalArgumentException("Interface class == null");
		}
		if(!interfaceClass.isInterface()){
			throw new IllegalArgumentException("The " + interfaceClass.getName() + " must be interface class!");
		}
		if(host == null || host.length() == 0){
			throw new IllegalArgumentException("Host == null!");
		}
		if(port <= 0 || port > 65535){
			throw new IllegalArgumentException("Invalid port " + port);
		}
		System.out.println("Get remote service " + interfaceClass.getName() + " from server " + host + ":" + port);
		return (T) Proxy.newProxyInstance(interfaceClass.getClassLoader(), new Class<?>[] {interfaceClass}, new InvocationHandler(){
			public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
				Socket socket = new Socket(host, port);
				try{
					ObjectOutputStream output = new ObjectOutputStream(socket.getOutputStream());
					try{
						output.writeUTF(method.getName());
						output.writeObject(method.getParameterTypes());
						output.writeObject(args);
						ObjectInputStream input = new ObjectInputStream(socket.getInputStream());
						try{
							Object result = input.readObject();
							if(result instanceof Throwable){
								throw (Throwable) result;
							}
							return result;
						} finally{
							input.close();
						}
					} finally{
						output.close();
					}
				} finally{
					socket.close();
				}
			}
		});
	}
}
